Imaging process and article employing photolabile, blocked surfactant

ABSTRACT

A photosensitive element is provided by an actinic radiation-transmissive film-forming polymeric material which contains photolabile blocked surfactant capable upon exposure to actinic radiation of releasing a detectable quantity of surfactant in actinic radiation exposed areas in areas not exposed to actinic radiation and unblocked surfactant in an image-wise pattern in the actinic radiation exposed areas. An imaging process is also provided comprising providing the actinic radiation-sensitive element and exposing the actinic radiation-sensitive element to actinic radiation in an image-wise pattern at an intensity and for a time sufficient to release an image-wise pattern of released surfactant in the exposed area.

This is a division of application Ser. No. 177,287 filed Aug. 11, 1980,U.S. Pat. No. 4,369,244.

DESCRIPTION TECHNICAL FIELD

This invention relates to graphic arts and particularly to improvedphotosensitive elements and imaging processes comprising photolabileblocked surfactants.

BACKGROUND ART

Photosensitive elements suitable for use in printing plates andinformation recording films are well known and the subject of a greatmany publications and patents. Since the advent of photopolymerchemistry about 35 years ago, increasing effort has been made todisplace silver halide as the photosensitive material in photosensitiveelements with more or less success. Most of these non-silver containingphotosensitive elements have utilized compositions containing moietieswhich polymerize on exposure to suitable radiation to yield polymer inexposed areas of the element. On development of the exposed element witha solvent, in composition in unexposed areas can be removed to produce adeveloped element that may be used as a printing plate, a projectiontransparency or for information recording and the like. Photosensitiveelements utilizing photopolymerization are less than desirable becauseimage contrast attainable is generally low and because of the necessityof using solvents to develop the image.

DISCLOSURE OF INVENTION

In accordance with the present invention, there is provided a non-silverprocess for formation of images and imaged articles which does not relyon photo-induced polymerization. Therefore, the present process avoidsthe above-mentioned problems attendant with photo-inducedpolymerization. The process and articles of the inventions employ as thephotosensitive element a photolabile blocked surfactant. The articles ofthe invention may provide driographic- and lithographic-type printingplates, projection transparencies, and high resolution informationrecording films.

The photolabile blocked surfactants useful in the present invention aresurfactants (i.e., compounds characterized by having a hydrophobic groupand at least one polar hydrophilic group ) having the polar group(s)masked by a covalently bonded labile masking group. Because of thephotolabile mask, the masked surfactant has substantially reducedsurfactant activity as compared to the same surfactant in the unmaskedstate and, on exposure to suitable radiation, the mask is removed,substantially restoring the surfactant to its original surface activity.

Specifically, the photolabile surfactant compounds useful in the presentinvention have the general formula (P--X)_(a) R wherein (--X)_(a) R isthe hydrogen-eliminated residue of a surfactant having the formula(H--X)_(a) R including the polar divalent radical X, P is a covalentlybonded photolabile masking group which prior to exposure to actinicradiation masks the polar properties of X and upon exposure to actinicradiation will unmask the polar properties of X, and R is a hydrophobicgroup which provides in the surfactant (H--X)_(a) R a log (criticalmicelle concentration, hereinafter designated "CMC") equal to or lessthan -2 and "a" is a number from 1 to 4 to satisfy the valency of R.

The process of the invention comprises at least two basic steps. Thefirst step involves providing an actinic radiation-sensitive film orlayer comprising a blend of an actinic radiation-transmissivefilm-forming polymeric material and photolabile blocked surfactantcapable upon exposure to actinic radiation of releasing a detectableamount of surfactant in the exposed areas. The film may be aself-supporting sheet or as a layer carried on an appropriate support orone layer in a multi-layered construction. The second step involvesexposing the actinic radiation-sensitive layer to actinic radiation inan image-wise pattern at an intensity and for a time sufficient toprovide an image-wise pattern of released surfactant in the exposedarea. By these steps, an article is obtained comprising a film or layerwithin a construction having surface areas of differential oleophobicitybecause of the higher concentration of released surfactant in theexposed areas than in the unexposed areas.

A driographic ink having a greater affinity for the exposedsurfactant-containing areas than the non-exposed areas may be applied tothe surface of the exposed film to develop the exposed image or toprovide a negative (reversal) image which may be transferred from thefilm surface to another substrate such as paper. Alternatively, thedriographic ink and film binder may be selected such that the ink has agreater affinity for the unexposed areas than for the exposed areas andthereby utilized to produce a positive image which may also betransferred to another substrate.

In another aspect, the process comprises the two basic steps describedabove, except that the actinic light sensitive film is as a layer coatedon a support which is selected so that it has the ability to retainreleased surfactant on its surface. The process includes the additionalstep of separating the exposed actinic radiation-sensitive layer fromthe support. By this step, an article is obtained comprising the supporthaving released surfactant in an image-wise pattern but otherwise beingsubstantially free of surfactant in unexposed areas. The image of theresultant article (the surfactant-imaged support) may be developed withdriographic ink as described above or with a lithographic ink with afountain solution.

In yet another aspect of the invention, the process involves providing asupport layer and an actinic radiation-sensitive layer which areselected so that the adhesion of the actinic radiation for the supportlayer is greater in unexposed areas than in exposed areas. The nextprocess step involves in either order exposing the actinicradiation-sensitive layer to actinic radiation and applying to theactinic radiation-sensitive layer an adherent layer. The adherent layermust be actinic radiation-transmissive if applied prior to exposure. Thematerials are selected to that the exposed area of the actinicradiation-sensitive layer has greater adhesion for the adherent layerthan for the support layer, and the adhesion of the unexposed area ofthe actinic radiation-sensitive layer is greater for the support layerthan for the adherent layer and the cohesion of the actinicradiation-sensitive layer is (1) greater than the adhesion between theexposed area of the actinic radiation-sensitive layer and the supportlayer; (2) greater than the adhesion between the unexposed areas and theadherent layer, and (3) less than the adhesion between the unexposedarea of the actinic radiation-sensitive layer and the support layer. Thenext step involves separating the adherent layer from the exposedarticle to cause separation of the actinic radiation-sensitive layerremaining bonded as a negative image (corresponding to the actinicradiation pattern) to the adherent layer. The image may then bedeveloped by applying dye or toner powder to either or both the negativeimage-bearing adherent layer and the positive image-bearing support.

In a further aspect of the invention, the process comprises providing afour-layered construction comprising a radiation-transmissive supportlayer having thereon an actinic radiation-sensitive layer which hasthereon a frangible-dyed or -opaque layer which is covered by anadherent layer. The various layers are selected of materials such that(1) the adhesion between the actinic radiation-sensitive layer and thesupport layer is less in exposed areas than in unexposed areas, (2) theadhesion between the exposed area of the actinic radiation-sensitivelayer and the support layer is less than the adhesion between thefrangible layer and the adherent layer, (3) the adhesion between theadherent layer and the frangible layer is less than the adhesion betweenthe unexposed area of the actinic radiation-sensitive layer and thesupport layer, (4) the adhesion between the frangible layer and theexposed and unexposed areas of the actinic radiation-sensitive layer isgreater than the adhesion between any other layers and (5) the cohesionof the frangible layer is (a) greater than the adhesion between thesupport layer and the exposed area of the actinic radiation-sensitivelayer and (b) greater than the adhesion between the frangible layer andthe adherent layer and (c) less than or equal to the adhesion betweenthe radiation-sensitive layer and the frangible layer. The process theninvolves exposing the actinic radiation-sensitive layer to an image-wisepattern through the radiation-transmissive support and separating theadherent layer from the support layer. This produces an imaged adherentlayer having a positive image of opaque or dyed material derived fromthe frangible layer and an imaged radiation-transmissive support layerbearing the actinic radiation-sensitive layer having a negative opaqueor dyed image also derived from the frangible layer which would providea useful overhead transparency.

In a further aspect of the invention, the process comprises providing athree-layered construction comprising a support layer, an intermediatefrangible layer, and an actinic radiation-sensitive layer. The actinicradiation-sensitive layer is then exposed in an image-wise pattern toactinic radiation and an adherent layer is applied to the exposedactinic radiation-sensitive layer. If the adherent layer is actinicradiation-transmissive, the exposure may be either before or afterapplication of the same to the actinic radiation-sensitive layer. Thevarious layers are selected of materials such that (1) the adhesionbetween the actinic radiation-sensitive layer and the frangible layer isgreater in unexposed areas than in exposed areas, (2) the adhesionbetween the exposed area of the actinic radiation-sensitive layer andthe frangible layer is less than the adhesion between the frangiblelayer and the support layer, (3) the adhesion between the unexposed areaof the actinic radiation-sensitive layer and the frangible layer isgreater than the adhesion between the frangible layer and the supportlayer, (4) the adhesion between the adherent layer and the exposed andthe unexposed areas of the actinic radiation-sensitive layer is greaterthan the adhesion between any other layers, and (5) the cohesion of thefrangible layer is such that it separates at the lines defining theimage. After exposure and application of the adherent layer, the layersare separated to provide the support layer bearing the negative imagederived from the frangible layer and a two-layered construction of theadherent layer bearing the actinic radiation-sensitive layer which hason its surface a positive image derived from the frangible layer.

It should be noted that the mobility of released surfactant may beincreased upon application of heat, either during or after exposure. Instill a further aspect of the invention, the process comprises firstproviding a three-layered construction having a support layer, anintermediate frangible layer, and an actinic radiation-sensitive layer.The frangible layer may be translucent, transparent, but preferably isopaque. The actinic radiation-sensitive layer is then uniformly exposedto actinic radiation to provide released surfactant throughout. Theuniformly exposed actinic radiation-sensitive layer is then furtherexposed to an image-wise pattern of thermal radiation. The materials areselected so that (1) the adhesion between the frangible layer and theactinic radiation-sensitive layer is greater in non-thermally exposedareas than in thermally exposed areas, (2) the adhesion between thethermally exposed area of the actinic radiation-sensitive layer and thefrangible layer is less than the adhesion between the frangible layerand the support layer, (3) the adhesion between the non-thermallyexposed area of the actinic radiation-sensitive layer and the frangiblelayer is greater than the adhesion between the frangible layer and thesupport, and (4) the cohesion of the frangible layer is greater than (a)the adhesion between the frangible layer and the thermally exposed areaof the actinic radiation-sensitive layer and (b) the adhesion betweenthe frangible layer and the support layer. An adherent layer havingadhesion to the exposed and the unexposed areas of the actinicradiation-sensitive layers greater than the adhesion between the otherlayers is applied to the imaged actinic radiation-sensitive layer, andthe adherent layer is separated from the construction. This causes thefrangible layer to separate producing an imaged support having apositive image derived from the frangible layer corresponding to thethermally exposed area and, if the support is transparent to visiblelight, transparent areas corresponding to thermally unexposed areas,providing a unique visual transparency.

DESCRIPTION OF THE DRAWING

The invention is further illustrated by reference to the accompanyingdrawings wherein each view is a greatly enlarged elevational view incross-section and:

FIG. 1 is an actinic radiation-sensitive film useful in the presentinvention;

FIG. 2 is a construction comprising a support layer bearing an actinicradiation-sensitive layer which is being exposed to actinic radiation inan image-wise pattern;

FIG. 3 is the exposed construction of FIG. 2 developed to provide avisible image pattern;

FIG. 4 is another embodiment of the invention showing the actinicradiation-sensitive layer being separated from a support layer bearing adeveloped image-wise pattern of surfactant;

FIG. 5 is yet another embodiment of the present invention comprising asupport layer, an intermediate actinic light-sensitive layer which hasbeen exposed to actinic radiation and an adherent layer;

FIG. 6 shows the exposed article of FIG. 5 with parts being partiallyseparated to reveal image patterns;

FIGS. 7 and 8 respectively show the separated parts of the embodiment ofFIG. 6 with each of the image patterns being developed;

FIG. 9 shows yet another embodiment of the present invention comprisingan adherent base layer bearing a frangible layer having thereon anactinic light-sensitive layer which is being imaged with actinic radiati

FIG. 10 shows the exposed article of FIG. 9 being separated into parts;

FIG. 11 shows yet another embodiment of the present invention comprisinga support layer, an intermediate frangible layer and an actinicradiation-sensitive layer which has been exposed to an image-wisepattern;

FIG. 12 shows the embodiment of FIG. 11 having had an adherent layerapplied to the exposed actinic radiation-sensitive layer and beingseparated to cause image-wise separation of the frangible layer;

FIG. 13 shows yet another embodiment of the present invention comprisinga support layer, an intermediate frangible layer and an actinicradiation-sensitive layer which has been uniformly exposed to actinicradiation and is being thermally imaged in an image-wise pattern; and

FIG. 14 shows the embodiment of FIG. 13 after application of an adherentlayer and separation.

DETAILED DESCRIPTION

Referring now to FIG. 1, there is shown a self-supporting film 10 ofactinic radiation-sensitive sheet 12 comprised of a film-forming bindercontaining a photolabile surfactant capable of releasing surfactant inan image-wise pattern upon exposure to actinic radiation. FIG. 2 showsthe actinic radiation-sensitive layer 12 coated upon support layer 11,e.g., a film to provide layered construction 13. Actinicradiation-sensitive layer 12 is capable upon being exposed by actinicradiation source 20 with actinic radiation 21 in an image-wise patternby utilizing a suitable device 22 having an image-wise pattern opening23 capable of permitting the passage of actinic radiation. Uponexposure, actinic radiation-sensitive layer 12 is characterized byhaving a higher concentration of released surfactant in exposed area 24than in unexposed area 25.

Upon exposure, the surface of the actinic radiation-sensitive layer maybe developed by application of a suitable material, e.g., ink or tonerto provide developed layer 30. Alternatively, the actinicradiation-sensitive layer 12 and support layer 11 may be selected suchthat layer 12 may be separated from support layer 11, as shown in FIG.4, leaving an image-wise pattern of surfactant on the surface of support11 which also may be developed by application of a suitable ink or tonerto provide image-wise developed layer 40.

Alternatively, as shown in FIGS. 5-8, an adherent layer 50 may beapplied to the surface of exposed actinic radiation-sensitive layer 12and the respective layers selected of materials so that the adhesion ofthe actinic radiation-sensitive layer 12 for the support layer 11 isgreater in unexposed areas 25 than in exposed areas 24 and the adhesionbetween adherent layer 50 and actinic radiation-sensitive layer 12 isgreater than the adhesion of the actinic radiation sensitive layer forthe support in exposed areas 24, but less than in unexposed areas 25.Separating adherent layer 50 from the construction will separate actinicradiation-sensitive layer 12, as shown in FIG. 6, leaving support layer11 bearing a negative image area 25 of actinic radiation-sensitive layerand adherent layer 50 bearing a positive image area 24 of the actinicradiation-sensitive layer. As shown in FIGS. 6 and 7, respectively, eachof the separated parts may be developed to provide a developed positiveimage pattern 70, as shown in FIG. 7, or negative developed imagepattern 80, as shown in FIG. 8.

Referring now to FIG. 9, there is shown a four-layered construction 100comprising adherent layer 50, frangible layer 91, actinicradiation-sensitive layer 12, and actinic radiation-transmissive supportlayer 90. Exposing actinic radiation-sensitive layer 12 to actinicradiation through support layer 90 produces negative image pattern 24and positive pattern 25. Separation of the support layer 90 fromadherent layer 50 results in a separation of frangible layer 91, asshown in FIG. 10. The materials are selected so that the adhesion of theactinic radiation-sensitive layer 12 for the support layer 90 is less inexposed areas than in unexposed areas, a separation will occur asdepected in FIG. 10 wherein area 92 of the frangible layer adjacent andexposed area 24 of actinic radiation-sensitive layer 12 separate fromthe support remaining bonded to adherent layer 50, leaving positiveimage 93 of frangible layer 91 and adjacent unexposed area 25 adhered tothe support layer 90.

Referring now to FIG. 11, there is shown a three-layered construction120 comprising support 11, intermediate frangible layer 91 and actinicradiation-sensitive layer 12. Exposing actinic radiation-sensitive layer12 to actinic radiation produces negative image pattern 24 and positiveimage pattern 25. Application of adherent layer 50 to exposed actinicradiation-sensitive layer 12 and separation of adherent layer 50 andsupport layer 11 causes construction 120 to separate as shown in FIG.12, leaving negative image 92 adherently bonded to the support andleaving positive image 93 adherently bonded to a two-layeredconstruction of adherent layer 50 and exposed actinicradiation-sensitive layer 12, both image pattern 93 and 92 beingobtained from frangible layer 91.

Referring now to FIGS. 13 and 14, there is shown a three-layeredconstruction 130 comprising support 11, intermediate frangible layer 91and actinic radiation-sensitive layer 12 which has been exposed toactinic radiation uniformly to provide exposed areas 24 and which hasalso been heated by heated element 140 to provide image pattern 141which is characterized by having a lower adhesion for frangible layer 91than areas 24 have for frangible layer 91. Application of adherent layer50 to the exposed surface and separation of the layers results in theconstruction shown in FIG. 14, leaving support layer 11 bearing negativeimage pattern 92 and the two-layered construction of adherent layer 50and actinic radiation-sensitive layer 12 bearing positive image 93, bothbeing obtained by separation of frangible layer 91.

The photolabile blocked surfactants and the film-forming binder suitablefor use in the actinic light sensitive layer of the present inventionare described in assignee's copending application U.S. Ser. No. 177,288filed Aug. 11, 1980. The disclosure of said application is incorporatedherein by reference for the description of the photolabile blockedsurfactant, the film-forming binder materials and the process of coatingblends of these to produce actinic light-sensitive layers.

As described in that application, useful surfactants are those which, intheir salt form, are commonly known as ionic surfactants. Suitable ionicsurfactants are those having one or more salt-forming polar groupincluding carboxylic, sulfonic, phosphonic, phosphinic, sulfinic, aminoand the like polar groups.

Suitable photolabile masking groups for use in the photolabile blockedsurfactants (sometimes referred to as photoactivatable release agents)of the invention are any of the photolabile masking groups (often termedprotecting groups) recognized in organic chemistry, particularly thechemistry of aminoacids. Examples of such protecting groups include2-nitrobenzyl, phenacyl, decyl, 2-nitroanilino,2,4-dinitrobenzenesulfenyl, 2-(2-azidoaryl)ethyl, 7-nitroindolino,β-nitrocinnamyl, and 8-nitrotetrahydroquinolino groups that can besubstituted by one or more auxochromic or bathochromic groups.

Preferred photolabile blocked surfactants of the invention include thoseof the formula (P--X)_(a) R wherein

P is defined above; and

X is a polar group selected from ##STR1## wherein R¹ is selected fromhydrogen and lower alkyl having one to four carbon atoms;

R is selected from: ##STR2## wherein R² is

(1) a straight chain alkyl, alkenyl, alkynyl or alkylphenyl group having12 to 30 carbon atoms when X is ##STR3##

(2) a straight chain alkyl, alkenyl, alkynyl or alkylphenyl group having15 to 30 carbon atoms when X is ##STR4## wherein R¹ is defined above; or

(3) a perfluoroalkyl, -alkenyl, or -alkynyl group having 7 to 30 carbonatoms;

R³ is a straight chain alkyl, alkenyl, alkynyl or alkylphenyl or grouphaving 11 to 30 carbon atoms or a perfluoralkyl group having 7 to 30carbon atoms;

R⁴ is a straight chain alkyl, alkenyl, alkynyl, alkylphenyl orperfluoroalkyl, -alkenyl, or -alkynyl group having 7 to 30 carbon atoms;

n is 1 or 2; and

a is 1.

The most preferred photolabile blocked surfactants of the invention havethe general formulae: ##STR5## wherein X, R and R¹ are as defined above;

Ar¹ is a mononuclear or polynuclear divalent aryl group having 6 to 14carbon atoms or heteroaromatic group having 5 to 13 carbon atoms withheteroatoms selected from oxygen, nitrogen or sulfur atoms, the nucleiof which may be substituted by one or more auxochromic or bathochromicgroups, examples of which include nitro, chloro, bromo, phenyl, loweralkyl, lower alkoxy, lower thioalkoxy, amino, lower alkyl ordialkylamino, and the like groups and the aryl group Ar¹ may be the arylgroup in a polymer;

Ar² is preferably the same as Ar¹ except that Ar² is monovalent;

R⁵ is preferably hydrogen but may be lower alkyl or phenyl which mayalso be substituted by an auxochromic or bathochromic group as definedfor Ar, or a lower alkylene group joining CH to Ar and forming a five-or six-membered heterocyclic ring;

R⁶ is preferably phenyl substituted by 3-alkoxy or 3,5-dialkoxy in whichthe alkyl group has 1 to 4 carbon atoms but can be a hydrogen atom, alower alkyl group, e.g., having from 1-3 carbon atoms, or a phenylgroup;

R⁷ can be hydrogen but preferably is lower alkyl having 1 to 4 carbonatoms or most preferably is lower alkylene having 2 to 4 carbon atomsjoining N to Ar¹ forming a five- or six-membered heterocyclic ring; and

b is zero or one.

A simple infrared spectroscopic analysis technique may be employed toidentify the suitable photolabile covalently bonded blocked surfactantsof the present invention. In this technique, a small amount (e.g., about10-100 mg) of the test photolabile blocked surfactant (as a thin liquidfilm or as a mull in mineral oil) is analyzed to obtain an infraredspectrum. The sample is thereafter exposed to an ultraviolet source(e.g., using an H3T7 lamp from a distance of 5 cm) for a brief length oftime and a second IR spectrum is obtained of the UV exposed sample.Useful compounds will show a change in the infrared spectrum due tobreaking of the covalent bond and liberation of the polar group of theunblocked surfactant after UV light exposure. The UV light exposure timeneeded to cause this change will generally depend on several factorsincluding the photosensitivity of the test compound, film thickness,etc. Generally, exposures of from 5 to 50 minutes will be sufficient and15-30 minute exposures are more common.

The film-forming binder component of the actinic radiation-sensitivelayer of the construction of the invention are thermoplastic organicpolymers preferably having a molecular weight of at least 10,000.Suitable polymers include: (a) copolyesters based on terephthalic,isophthalic, sebacic, adipic and hexahydrophthalic acids such polyesterssold under the trade designation "Vitel" by the B. F. Goodrich Company,(b) polyamides such as poly(hexamethyleneadipamide) and polycaprolactam,(c) vinyl acetate polymers such as that available under the tradedesignation VINAC ASB516 from Air Products Company and vinyl chloridecopolymers such as the copolymer with vinyl acetate, e.g., that soldunder the trade designation VMCH, VAGH, or VYHH by the Union CarbideCompany and under the trade designation "Geon" resin by the B. F.Goodrich Company, (d) vinyldine chloride copolymers (e) ethylenecopolymers, e.g., ethylene or propylene and vinyl acetate, (f)polyacrylates such as polymethyl and methacrylate and the copolymers ofacrylic acid esters with other ehtylenically unsaturated monomers, e.g.,that sold under the trade designation "Carboset 525" by the B. F.Goodrich Company and methacrylate resins such as that sold under thetrade designation "Elvacite" by the duPont Company, the pressuresensitive adhesive copolymers of "soft" acrylic esters such as butyl orisooctyl acrylate and a " hard" monomer such as acrylic acid oracrylamide, (g) cellulose esters such as cellulose acetate/butyrate, (h)polyvinyl acetals such as polyvinyl butyral, (i) polyurethanes, (j) thepolycarbonates, and (k) styrene-maleic anhydride or maleic acidcopolymers.

Suitable supports for bearing the actinic light sensitive layer incudeglass, metal, ceramic, paper and polymeric supports. The form of thesupport may be any form and its should be selected depending upon theparticular application of the process or article. The preferred supportsare flexible sheets. Particularly suitable supports are polyester,polyolefin, polyamide films, polyvinyl chloride, polyvinylidene chlorideand polyvinylidene fluoride.

Suitable frangible layers include layers of metal, oxide and dyed orpigmented polymeric material. The metal or metal oxide layers may beelectro-, chemically-, sputter-, or preferably vapor-deposited singly onin successive combination. Suitable metals and metal oxides includealuminum, aluminum oxide, copper gold, nickel, silicon oxide, tin, zinc,etc. Useful thickness as of such layers may vary from 50 to 4000 Å,preferably 250 to 1500 Å, depending on the desired image density and thespecific layer.

Suitable adherent layers are provided by flexible foils, films and othersheet goods having at least one surface which is inherently adhesive oris coated with a layer of adhesive material such as a layer ofpressure-sensitive adhesive material. A preferred adherent layer isprovided by a layer of polymeric film coated with a pressure-sensitiveadhesive material such as an arylate-type pressure-sensitive material,e.g., that disclosed in Ulrich (U.S. Pat. No. Re. 24,906), assigned tothe present assignee.

Suitable development dyes and toners which have a high affinity for theactinic light-sensitive layers include basic dyes such as auramine,Intradene yellow, Rhodamine, Safranine T, and Crystal Violet, and tonerssuch as those sold under the trade designations "Magna" Dry Type 842 and361; "Magna Dynamic" and "ESP" by the assignee of the presentapplication.

The composition forming the actinic light sensitive layer may beprepared by mixing by any convenient method the film-forming binder andphotolabile surfactant in a suitable solvent. The ratio of thephotolabile surfactant to film-forming binder will be on the order of1:100 to 10:100, preferably 2:100 to 4:100. Solutions are prepared tocontain about 10 to 50 weight percent concentration of solids, theconcentration used being that which provides a solution having aviscosity more suitable to the method by which the composition isapplied to the support.

Solvents for use in the coating composition are chosen on the basis ofthe film-forming binder. Suitable solvents include ketones such asacetone, methylethylketone, and methylisobutyl ketone; aromatichydrocarbons such as benzene and toluene; halocarbons such aschloroform, methylene chloride, and trichloroethylene; esters such asethyl acetate and propyl butyrate; ethers such as diethyl ether,dioxane, and tetrahydrofuran; nitromethane; nitroethane; andacetonitrile.

The coating may be applied to the substrate by any conventional means,including spray, brush, dip pad, roll coating, curtain and knifetechniques, and may, if desired, be dried under ambient or otherconditions to provide the actinic light sensitive layer. The coatingthickness, after drying, will be on the order of 0.5 to 50 micrometers,preferably 1 to 10 micrometers.

Various additives may be included in the actinic light sensitive layerto accomplish various purposes. For example, photosensitizers may beadded to broaden the exposure sensitivity of the actinic light sensitivelayer. Various other additives common to the photographic andlithographic arts may also be added for known purposes.

In the process of the invention, the construction may be exposed to anysource of radiation emitting actinic radiation at a wavelength withinthe ultraviolet and visible spectral regions. Suitable sources ofradiation include mercury, xenon, carbon arc and tungsten filamentlamps, lasers, sunlight, etc. Exposures may be from less than about 1second to 10 minutes or more depending upon the amounts of theparticular photolabile blocked surfactant being utilized and dependingupon the radiation source, distance from the source, and the thicknessof the active radiation-sensitive layer.

The invention is further illustrated by the following examples whereinall parts are by weight, unless otherwise specified.

EXAMPLES 1-6

Examples 1-6 illustrate the preparation of driographic printing platesutilizing photolabile surfactants according to the invention.

A series of solutions were prepared to contain 5% by weight ofphotolabile surfactant based on binder by adding 0.025 g of thephotolabile blocked surfactant to 5 g of 10% solutions of the binder.The solutions were coated onto anodized, silicated aluminum and thecoatings dried at 65° C. Table I gives the photolabile blockedsurfactant (designated PR Agent), binder and solvent used for preparingeach coating. The coatings were exposed for 3-5 minutes at a distance of5 to 18 cm through a metal stencil to the irradiation from a G.E. H3T7source. Using a rubber roller, each exposed coating was then inked withDRK driographic ink (available form L. O. Wernecke Company, Minneapolis,Minn.).

                  TABLE I                                                         ______________________________________                                                               Binder                                                                        Trade                                                  Ex.                    Desig-          Ink                                    No.  PR Agent          nations  Solvent                                                                              Action                                 ______________________________________                                        1.   2-Nitrobenzylperfluoro-                                                                         "Kraton" Toluene                                                                              Pos.sup.(4)                                 octanoate         1101.sup.(1)                                           2.   3'-Methoxybenzoin "Kraton" Toluene                                                                              Pos.                                        perfluorooctanoate                                                                              1101                                                   3.   4,5-Dimethoxy-2-nitrobenzyl                                                                     "Kraton" Toluene                                                                              Pos.                                        perfluorooctanoate.sup.(7)                                                                      1101                                                   4.   4,5-Dimethoxy-2-nitrobenzyl                                                                     "Kraton" Toluene                                                                              Pos.                                        perfluorooctanoate.sup.(7)                                                                      G-1652.sup.(2)                                         5.   2-Nitrobenzyl hexadecane-                                                                       "Emer-   Ethanol                                                                              Neg..sup.(5)                                sulfonate         ez"                                                                           1537.sup.(3)                                           6.   2-Nitrobenzyl perfluoro-                                                                        "Kraton" Toluene                                                                              None.sup.(6)                                butanoate         1101                                                   ______________________________________                                         .sup.(1) Polystyrenebutadiene copolymer available from Shell Chemical         Company.                                                                      .sup.(2) Polystyrenepoly(ethylene-butylene) copolymer available from Shel     Chemical Company.                                                             .sup.(3) Polyamide resin available from Emery Industries, Inc.                .sup.(4) Ink adheres to unirradiated areas but not to irradiated areas.       .sup.(5) Ink adheres to irradiated areas but not to unirradiated areas.       .sup.(6) Ink adheres to both irradiated and nonirradiated areas. Compound     liberated in irradiated areas does not appreciably change the                 characteristic of the binder for being wet by ink.                            .sup.(7) Can be imaged with a Berkey Ascor 2 kW exposure unit through a       lithographic film original.                                              

EXAMPLE 7

This example illustrates the preparation of an adhesive image on analuminum foil support.

Into 4.0 g of a 25% solution of pressure-sensitive adhesive[poly(2-methylbutylacrylate/acrylic acid)-90/10] in acetone-heptane wasmixed 0.025 g of 2-nitrobenzyl hexadecanesulfonate in 4.0 g of methylethyl ketone. The resulting adhesive solution was knife coated at a 50μm orifice onto 50 μm polyester film. The coating was air dried and thecoated film cut into strips. Strips were then placed coated side downonto strips of aluminum and, while heating the aluminum gently with ahot air gun, were pressed with a hard rubber roller. The polyestersurface of the polyester/adhesive/aluminum laminate 180° angle and apull rate of about 5 to 20 cm/sec. A positive image (from the unexposedareas) of the stencil in adhesive was obtained on the aluminum strip andthe complementary negative image (exposed areas) of the stencil inadhesive remained on the polyester layer. The adhesive images could beenhanced by toning with toner powder or by dyeing with basic dyes.

Similar results are obtained with laminates prepared by coating theadhesive solution onto aluminum, allowing the coating to dry, andlaminating the polyester film to the coating.

Laminates made as described above but not using a photolabile surfactantin the adhesive layer did not yield images.

Examples 8 and 9 illustrate other constructions for preparing adhesiveimages on met

An adhesive solution composed of poly(isooctylacrylate-acrylicacid)-95/5, 32% in heptane and containing 10% 2-nitrobenzylheptadecanoate based on solids was knife coated at 50 μm orifice ontopolyester film. The coating was air dried and pressed adhesive side downonto Parker Bonderite 40 phosphated steel panels*. The constructionswere irradiated for six minutes at 2.5 cm with a G.E. H3T7 lamp througha metal stencil. The polyester film was peeled at 180° to reveal apositive image of adhesive on steel (adhesive is released from the steelin exposed areas) and a complementary positive image simultaneously onthe polyester peel-off layer.

EXAMPLE 9

Example 8 was repeated using in place of 2-nitrobenzyl heptadecanoate,3'-methoxybenzoin perfluorooctanoate as photolabile surfactant. Adhesiveimages similar to those obtained in Example 8 were prepared.

EXAMPLES 10-13

A methylethyl ketone solution containing 15% "Vitel" PE-222 (a polyesterresin available from Goodyear Chemicals, Inc.) as binder resin and 0.95g of 4,5-dimethoxy-2-nitrobenzyl octadecanoate (6% by weight of solidsin the solution) as PR Agent was coated with a No. 25 coating rod onto asheet of aluminized polyester (450 Å thick layer of vapor coatedaluminum on a 75 μm thick polyester base). The air dried (30 minutes)sample was exposed thorugh a lithographic film negative developed byapplying the adhesive surface of a pressure-sensitive adhesive sheet tothe resin coating and peeling the adhesive sheet versus the base. Resincoating and aluminum were removed with the adhesive sheet in unexposedareas and resin only in the exposed areas, leaving underlying aluminumto create a negative aluminum image (i.e., reversal) of the mask on thepolyester base. A complementary positive image comprised of aluminum wascreated on the adhesive sheet. Alternative PR Agents substituted for4,5-dimethoxy-2-nitrobenzyl octadecanoate at a 0.45% loading level (3%by weight of solids) gave similar results with the indicated times and a1.5 minutes post-exposure heating at 55° C. (TABLE II).

                  TABLE II                                                        ______________________________________                                        Ex.                           Exposure                                        No.      PR Agent             Time                                            ______________________________________                                        11       4,5-Methylenedioxy-2-nitrobenzyl                                                                   1.1 min                                                  perfluorooctanoate                                                   12       4,5-Dimethoxy-2-nitrobenzyl-                                                                       3 min                                                    N--octadecanoylsarcosinate                                           13       4,5-Dimethoxy-2-nitrobenzyl                                                                        0.75 min                                                 hexadecanesulfonate.                                                 ______________________________________                                    

EXAMPLE 14

The construction in Example 13 was also developed by foregoing the ovenheating step and proceeding as follows. The coated side of a sheet of 50μm polyester film bearing an approximately 25 μm thick layer of 50/50mixture of "Vitel" PE-207 (a polyester resin available from GoodyearChem. Inc.) and "Vitel" PE-222 polyester resin (solutin coated frommethylethyl ketone) was laminated to the UV-exposed surface of theconstruction in Example 13 by passing the contacted sheets through a hotroll laminator at 114° C. at a rate of 2.5 cm/sec. The sheets were thenpeeled apart to give results comparable to Example 13.

EXAMPLES 15-19

Metal images were prepared as described in Example 10 using eitherCarboset 525 (an acrylic resin available from B. F. Goodrich) or VitelPE-222 as the binder resin and the indicated PR Agent in the imaginglayer and 75-125 μm polyester film base bearing the noted vapordeposited materials (TABLE III).

                  TABLE III                                                       ______________________________________                                        Ex.                     Vapor                                                 No.  PR Agent (conc.)   Coating    Exposure                                   ______________________________________                                        15   4,5-Dimethoxy-2-nitrobenzyl                                                                      Copper.sup.(9)                                                                             5 min..sup.(10)                               hexadecanesulfonate (4%).sup.(8)                                         16   4,5-Dimethoxy-2-nitrobenzyl                                                                      Gold.sup.(9)                                                                               2 min..sup.(10)                               hexadecanesulfonate (3%).sup.(8)                                         17   4,5-Dimethoxy-2-nitrobenzyl                                                                      Nickel.sup.(9)                                                                             3 min..sup.(10)                               hexadecanesulfonate (3%).sup.(11)                                        18   N--Octadecyl-O--   Silicon    2.5 min.sup.(14)                                (4,5-dimethoxy     Monoxide                                              2-nitrobenzyl)carbamate                                                            over                                                                          (3%).sup.(11,12)   Aluminum.sup.(13)                                     19   N--Methyl-N--(4,5-dimethoxy                                                                      Silicon    1.5 min..sup.(12)                          2-nitrobenzyl) Monoxide                                                            octadecylamine     over                                                       (3%).sup.(11,15)   Aluminum.sup.(13)                                     ______________________________________                                         .sup.(8) Concentration in acrylic resin available under the trade             designation "Carboset" 525                                                    .sup.(9) Approximately 500Å coating                                       .sup.(10) Postexposure heating step not performed before peeling.             .sup.(11) Concentration in polyester resin available under the trade          designation "Vitel" PE222                                                     .sup.(12) Coating dried 2 minutes at 60° C. before exposure.           .sup.(13) Approximately 150Å of silicon monoxide vapor deposited over     approximately 300Å of aluminum.                                           .sup.(14) Postexposure heating 1.5 minutes at 60° C. prior to          peeling.                                                                      .sup.(15) Coating dried 5 minutes at 60° C. before exposure.      

EXAMPLE 20

Negative aluminum images on 75 μm thick polyester film were prepared asin Example 13 with a 90 second exposure using a 5 kW Berkey Ascorexposure unit. After hydrophilization of the aluminum images with an 8%solution of sodium metasilicate, an article is obtained that can be usedas a plate in an offset lithographic printing press to provide at leasttwo thousand clear impressions.

EXAMPLE 22

By treatment of a negative aluminum image prepared as described inExample 13 with a fluorochemical derivative of salicyclic acid, a platesuitable for preparation of more than 500 impressions in an offsetdriographic printing press is obtained.

EXAMPLE 23

A sample of clay-filled Kraft paper which has been coated with a vinylchloride-fluoropolymer coating that is abhesive towards driographic inkwas vapor coated with 450 Å of aluminum to give a metal coating whichwas dull gray in appearance. This surface was coated with a 20% solutionof "Carboset" 525 acrylic resin containing 3%4,5-dimethoxy-2-nitrobenzyl hexadecanesulfonate using a No. 14 coatingrod. The sample was allowed to air dry to a tack-free surface, exposedthrough a lithographic negative to the irradiation from a Berkey Ascor 2kW unit for 45 seconds, and laminated to a pressure sensitive adhesivetape. On peeling the tape from the filled Kraft paper, an aluminum image(negative of the original) was obtained on the coated paper and apositive image was obtained on the tape. The imaged, coated paper, wheninked with a driographic ink, accepted ink in the aluminum areas and wasused to make satisfactory impressions.

EXAMPLE 24

A solution of 15% VYNS (high molecular 90/10 weight polyvinylchloride/polyvinyl acetate strippable resin from Union Carbide)containing 3% of solids ofN-methyl-N-(4,5-dimethoxy-2-nitrobenzyl)octadecylamine was coated with aNo. 26 coating rod onto silicated-anodized aluminum sheet. The coatingwas dried five minutes at 60° C. and imaged through a lithographic filmoriginal with a Berkey Ascor 2 kW exposure unit for 1.5 minutes. Thecoating was easily stripped completely from the metal surface with theaid of a sheet of adhesive film, leaving an image in liberatedsurfactant on the aluminum in irradiated areas. The aluminum surface wasinked with a lithographic fountain solution dampened applicator to giveink images in the irradiated areas only.

EXAMPLE 25

A sample prepared as in Example 13 was thoroughly dried by heating in a50° C. oven and then irradiated through a negative USAF resolutiontarget and a Stouffer Graphic Arts sensitivity guide with sufficientexposure (generally 0.75-1.5 minutes on the Berkey Ascor 2 kW unit) togive a "solid 3" on development (adhesive sheet lamination, 1.5 min. at55° C., peel). The resolution target produced had a resolution of 7/1 or143.4 line pairs/mm and an optical density of 2.7-3.0. Images preparedin this manner were suitable for use as exposure masks for the instantas well as other photosensitive materials. The process was also suitablefor reversal replication of slide transparencies from conventionalsilver halide film negatives.

EXAMPLE 26

A 15% solution in methylethyl ketone of "Vitel" PE-222 containing 3%4,5-dimethoxy-2-nitrobenzyl hexadecanesulfonate and about 0.1% VictoriaBlue dye was coated using a No. 26 coating rod onto polyester film, thesurface of which had been primed by exposure to a corona discharge. Thecoating was allowed to air dry and was exposed to the irradiation from aBerkey Ascor 2 kW unit thorugh a negative for 90 seconds. the surface ofthe resin coating was scored lightly and then laminated with pressuresensitive adhesive tape. On peeling the tape from the polyester, therewas revealed a positive image in blue resin on the polyester base and anegative image in blue resin on the tape.

EXAMPLE 27

Example 20 was repeated using 10 to 25% Franconia blue pigment (imperialA-4431) in place of Victoria Blue dye. Similar positive and negativeimages were obtained; exposure time, however, was 7 to 10 minutes fromthe polyester support side of the construction.

EXAMPLE 28

Polyester film (75 μm thick) that had been primed by exposure to coronadischarge was coated with a 5% soution in methylethyl ketone of "Vitel"PE-222 polyester resin containing 4% by weight of4,5-dimethoxy-2-nitrobenzyl hexadecanesulfonate using a No. 8 coatingrod. After air drying the coating, a 15% solution in methylethyl ketonecontaining 25% titanium dioxide was coated thereon using a No. 26coating rod. The coating was allowed to air dry, the coated surfacelaminated with pressure sensitive adhesive tape, and exposed to theirradiation from a Berkey Ascor 2 kW unit through a negative from thepolyester support side of the construction for 3 to 5 minutes. Onpeeling the tape from the polyester support, there was revealed apositive image in white on the polyester base and a negative image inwhite on the tape.

EXAMPLE 29

A sample was prepared as in Example 13 and exposed uniformly with aBerkey Ascor 2 kW exposure unit for three minutes. The coated surface ofthe sample was then contacted with the front side of a printed papersheet ("backprint" mode) and passed through the heated rollers of aThermofax® unit (thermal imaging device available from the 3M Co.) at1/3 to 1/2 maximum speed (3-7 cm/sec at 120°-135° C.). The sample wasthen separated from the printed original and the surface laminated withan adhesive sheet. On peeling, a replication of the original printedimage was obtained on the polyester base with the aluminum imagecorresponding to the printed image on the paper. The complementarynegative image in aluminum was obtained on the adhesive film. Similarresults were obtained with a printed transparency original.

We claim:
 1. An imaging process comprising:(1) providing an actinicradiation-sensitive film comprising a blend of:(a) an actinicradiation-transmissive film-forming polymeric material and (b) aphotolabile blocked surfactant has the general formula (P--X)_(a) Rwherein (--X)_(a) R is the hydrogen-eliminated residue of a surfactanthaving the formula (H--X)_(a) R wherein X is a polar hydrophilicdivalent radical; P is a convalently bonded photolabile masking groupwhich prior to exposure to actinic radiation masks the polar propertiesof X and upon exposure to actinic radiation will unmask the polarproperties of X; R is a hydrophobic group which provides in saidsurfactant (H--X)_(a) R a log (critical micelle concentration) equal toor less than -2; and a is a number from 1 to 4 to satisfy the valency ofR; and (2) exposing said actinic light sensitive film to actinicradiation in an image-wise pattern at an intensity and for a timesufficient to release an image-wise pattern of released surfactant inthe exposed areas of said film, said released surfactant being presentin a detectable amount and having a log critical micelle concentrationequal to or less than -2.
 2. The process of claim 1 comprising theadditional step of inking said image-wise pattern.
 3. The process ofclaim 1 wherein said film is a layer adherently bonded to a supportlayer.
 4. The process of claim 3 wherein said film and said supportlayer are selected so that they are capable of being separated afterexposure and said support layer is capable of retaining releasedsurfactant on its surface and including the step of inking the releasedsurfactant retained on said support layer.
 5. The imaging process ofclaim 3 wherein said support is formed of material selected from thegroup consisting of glass, metal, ceramic, paper and polymericmaterials.
 6. The imaging process of claim 3 wherein said support layeris a flexible sheet.
 7. The process of claim 6 wherein said supportlayer is a flexible sheet of polymeric material selected from the groupconsisting of polyester, polyolefin, polyamide, polyvinyl chloride,polyvinylidene chloride, and polyvinylidene fluoride.
 8. The process ofclaim 1 wherein X is selected from the group consisting of ##STR6##wherein R¹ is hydrogen or an alkyl group having from 1 to 4 carbonatoms.
 9. The process of claim 1 wherein said film-forming polymericmaterial is selected from the group consisting of polystyrene-butadienecopolymer, polystyrene-poly(ethylenebutyl) copolymer, polyamide,poly(isooctylacrylate-acrylic acid), polyester and mixtures thereof. 10.The process of claim 1 wherein said photolabile blocked surfactant isselected from the group consisting of 2-nitrobenzylperfuorooctanoate,3'-methoxybenzoin perfluorooctanoate, 4,5-dimethoxy-2-nitrobenzylperfluorooctanoate, 4,5-methylenedioxy-2-nitrobenzyl perfluorooctanoate,2-nitrobenzyl hexadecanesulfonate, 4,5-dimethoxy-2-nitrobenzylhexadecanesulfonate,4,5-dimethoxy-2-nitrobenzyl-N-octadecanoylsarcosinate,N-octadecyl-0-(4,5-dimethoxy-2-nitrobenzyl) carbamate, andN-methyl-N-(4,5 dimethoxy-2-nitrobenzyl)octadecylamine.
 11. An imagedfilm comprising:(a) an actinic radiation-transmissive film-formingpolymeric material; (b) a photolabile blocked surfactant has the generalformula (P--X)_(a) R wherein (--X)_(a) R is the hydrogen-eliminatedresidue of a surfactant having the formula (H--X)_(a) R wherein X is apolar hydrophilic divalent radical; P is a covalently bonded photolabilemasking group which prior to exposure to actinic radiation masks thepolar properties of X and upon exposure to actinic radiation will unmaskthe polar properties of X; R is a hydrophobic group which provides insaid surfactant (H--X)_(a) R a log (critical micelle concentration)equal to or less than -2; and a is a number from 1 to 4 to satisfy thevalency of R in areas of said film not exposed to actinic radiation; and(c) unblocked surfactant in an image-wise pattern in the actinicradiation exposed areas of said film, said unblocked surfactant beingpresent in a detectablcritical micelle concentration equal to or lessthan -2.
 12. A sheet construction comprising:(1) a support layer; and(2) bonded to one surface of said support an actinic radiation-sensitivelayer which has been exposed to actinic radiation in an image-wisepattern comprising:(a) an actinic radiation-transmissive film-formingpolymeric material having adhesion for said support; (b) a photolabileblocked surfactant has the general formula (P--X)_(a) R wherein(--X)_(a) R is the hydrogen-eliminated residue of a surfactant havingthe formula (H--X)_(a) R wherein X is a polar hydrophilic divalentradical; P is a convalently bonded photolabile masking group which priorto exposure to actinic radiation masks the polar properties of X andupon exposure to actinic radiation will unmask the polar properties ofX; R is a hydrophobic group which provides in said surfactant (H--X)_(a)R a log (critical micelli concentration) equal to or less than -2; and ais a number from 1 to 4 to satisfy the valency of R in areas of saidactinic radiation-sensitive layer not exposed to actinic radiation; and(c) unblocked surfactant in an image-wise pattern in the actinicradiation exposed areas of said actinic radiation-sensitive layer, saidunblocked surfactant being present in a detectable amount and having alog critical micelle concentration equal to or less than -2.
 13. Theactinic light sensitive sheet construction of claim 12 wherein X isselected from the group consisting of ##STR7## wherein R¹ is hydrogen ora lower alkyl group having from 1 to 4 carbon atoms.
 14. The actiniclight sensitive sheet construction of claim 12 wherein said film-formingpolymeric material is selected from the group consisting ofpolystyrene-butadiene copolymer, polystyrenepoly(ethylene-butylene)copolymer, polyamide, poly(isooctacrylate- acrylic acid), polyester, andmixtures thereof.
 15. The actinic light sensitive sheet construction ofclaim 12 wherein said photolabile blocked surfactant is selected fromthe group consisting of 2-nitrobenzylperfluoroorooctanoate,3'-methoxybenzoin perfluorooctanoate, 4,5-dimethoxy-2-nitrobenzylperfluorooctanoate, 4,5-methylenedioxy-2-nitrobenzyl perfluorooctanoate,2-nitrobenzyl hexadecanesulfonate, 4,5-dimethoxy-2-nitrobenzylhexadecanesulfonate,4,5-dimethoxy-2-nitobenzyl-N-octadecanoylsarcosinate,N-octadecyl-0-(4,5-dimethoxy-2-nitrobenzyl) carbamate, andN-methyl-N-(4,5dimethoxy-2-nitrobenzyl)octadecylamine.
 16. The actiniclight sensitive sheet construction of claim 12 wherein said support isformed of material selected from the group consisting of glass, metal,ceramic, paper and polymeric materials.
 17. The actinic light sensitivesheet construction of claim 12 wherein said support is a flexible sheet.18. The actinic light sensitive sheet construction of claim 12 whereinsaid support is a flexible sheet of polymeric material selected from thegroup consisting of polyester, polyolefin, polyamide, polyvinylchloride, polyvinylidene chloride, and polyvinylidene fluoride.